The topic we will be looking at is the human egg, which is the female seed. It is a large cell that is produced within the female reproductive cells , to enable reproduction. Just as with the male, this is a divine provision and enablement for every female to be able to bear children, upon meeting with a male seed, the sperm. God has created all human beings and givenÂ the power to reproduce with the coming together of a male and female seed.
The female reproductive system has two functions: The first is to
â€¢ produce egg cells, and the second is to
â€¢ protect and nourish the fetus until birth.
Reproductive cells, or gametes, have half of the genetic information required to form a new individual; thus, the meeting of a sperm with an egg results in a full set of chromosomes. Mature mammalian egg cells are relatively large–0.0039 inches. in diameter–and contain many proteins and protein precursors. This is because when a sperm cell introduces its genetic information to that of the egg, the egg must respond quickly so that cell division may begin and a new organism may form.
Egg cells also contain many mitochondria which supply the energy required for cell replication and division. Mitochondrial deterioration occurs with age and is thought to contribute to the difficulties experienced by many women trying to conceive children in their later years.
Egg cells are found in a special place within the body called ovaries. A woman is born with all of the egg cells she will ever have, but they do not present themselves for fertilization until after puberty. This is when ovulation first occurs. During the menstrual cycle, eggs that are maturing and preparing for ovulation are encased in ovarian structures called follicles.
As these particular eggs mature, the size of the follicles that contain them and the level of estrogen in the womanâ€™s body increases. This hormonal change contributes to the bodily changes experienced by many women halfway through the menstrual cycle, such as increased libido and thinning of cervical mucous. Ovulation occurs when one follicle bursts open, releasing the egg inside of it to the folds of the womanâ€™s fallopian tube.
Once inside of the fallopian tube, an egg cell has about 48 hours to live. If it is not fertilized by a sperm within this time, it will die. The follicle that released the egg is now called a corpus luteum, and it will secrete a hormone called progesterone for about two weeks after ovulation. If the egg remains unfertilized the corpus luteum will deteriorate and stop secreting hormones. This leads to the shedding of the uterine lining and the onset of menstruation.
If the egg comes into contact with sperm while it descends the fallopian tubes on its way to the uterus, fertilization may occur. The egg is covered in a thick membrane which the sperm must penetrate. Once inside of the egg, a chemical reaction takes place to keep other sperm from gaining entry. Meanwhile, the successful sperm cell will lose its tail while its DNA packed head will fuse with the nucleus of the egg.
The egg cell, or ovum, is the female reproductive cell (gamete) in females.Â The egg cell is typically not capable of active movement, and it is much larger (visible to the naked eye) than the motile sperm cells.
The human ovum consists of protoplasm that contains some yolk, enclosed by a cell wall consisting of two layers, an outer one (zona pellucida) and an inner, thin one (vitelline membrane). There is a large nucleus (germinal vesicle) within which is a nucleolus (germinal spot). The female reproductive cell which, after fertilization, becomes a zygote that develops into a new member of the same species.
The female sex cell. When fertilized by a sperm, a gamete or zygote is capable of developing into a new individual of the same species; during maturation, the oocyte, like the sperm, undergoes a halving of its chromosomal complement so that, at its union with the male gamete, the species number of chromosomes (46 in humans) is maintained; yolk contained in the oocyte varies greatly in amount and distribution, which influences the pattern of the cleavage divisions.
Eggs are huge. The human egg is a giant compared to other cells in the body. It has a diameter of about 100 microns (millionths of a meter), or roughly the thickness of a strand of hair. No other cell in the body is anywhere near that big.
The importance of the egg
An oocyte is an immature egg that develops from within a follicle inside in the ovaries. Normally one follicle will become a mature egg with each menstrual cycle. At birth a woman has all the oocytes that she will have for life. This number drops with age and after each normal menstrual cycle.
An oocyte will mature during the first week of the menstrual cycle. Up to two days before ovulation, the oocyte will be nourished by the surrounding cells. As this process happens, the surrounding cells start to proliferate and produce a high progesterone concentration. Then the follicle will release a fluid along with the oocyte to allow for a smooth flow of the mature egg to the fallopian tubes, where fertilization will take place. Follicle growth can be followed by conducting an ultrasound.
Its function is the formation of a Zygote to merge your kernel with the male gamete (spermatozoon), phenomenon called fertilization.
The woman is born with an already established endowment of oocytes that are progressively disappearing due to a phenomenon called atresia, so that upon reaching the age of puberty are approximately about 300,000 oocytes in the ovaries. In each menstrual cycle, an egg will run until ovulation and about 1,000 will be lost. In this way, at the age of 35 , aboutÂ 10% of the oocytes are lost.
It is common that in cases of age , because of the maternal advanced age , and the alreadyÂ is exhausted the ovarian reserve, it is more difficult to beÂ able to give rise to a healthy child.
The human egg
During fetal life, there are about 6 million to 7 million eggs. From this time, no new eggs are produced. At birth, there are approximately 1 million eggs; and by the time of puberty, only about 300,000 remain. Of these, only 300 to 400 will be ovulated during a womanâ€™s reproductive lifetime.
The female reproductive system provides several functions. The ovaries produce the female egg cells, called the ova or oocytes. The oocytes are then transported to the fallopian tube where fertilization by a sperm may occur. The fertilized egg then moves to the uterus, where the uterine lining has thickened in response to the normal hormones of the reproductive cycle. Once in the uterus the fertilized egg can implant into thickened uterine lining and continue to develop. If fertilization does not take place, the uterine lining is shed as menstrual flow. In addition, the female reproductive system produces female sex hormones that maintain the reproductive cycle.
During menopause the female reproductive system gradually stops making the female hormones necessary for the reproductive cycle to work. At this point, menstrual cycles can become irregular and eventually stop. One year after menstrual cycles stop, the woman is considered to be menopausal.
How many eggs does a woman have?
During fetal life, there are about 6 million to 7 million eggs. From this time, no new eggs are produced. At birth, there are approximately 1 million eggs; and by the time of puberty, only about 300,000 remain. Of these, only 300 to 400 will be ovulated during a womanâ€™s reproductive lifetime. Fertility can drop as a woman ages due to decreasing number and quality of the remaining eggs.
Factors that affect egg quality
Unfortunately as men and women age, both the sperm and the eggs are less able to form an embryo that can implant and form a normal offspring. A poor diet and poor lifestyle habits can worsen this process, or even cause poor egg and sperm quality in younger individuals. In the past, the marked reduction of fertility with age was attributed only to the female, but in large studies in which it has been possible to control for female age, and in studies of recipients of eggs from young egg donors, successful pregnancy was found to occur less often as the age of the male partner increases. Some exciting new findings outlined below indicate possible ways that judicious use of supplements may rejuvenate older sperm and eggs.
Diet and supplements
The testicles and ovaries need a good blood supply, which brings more nutrients, oxygen and hormones so that their functions can be optimized. For example, in the male, two agents known to increase nitric oxide, and therefore blood flow, increased the level of testosterone in the bloodstream and also significantly improved semen volume, sperm numbers, sperm motility, and sperm morphology. Testosterone production within the testicles is an important stimulator of normal sperm production. In the female, blood flow to the ovary correlates with the number of eggs that develop when the ovary is stimulated as well as the quality of the egg. Thus the chance of it initiating a pregnancy has been correlated with the blood supply surrounding the structure containing the egg and its nourishing cells, the granulosa cells.
A better diet with more antioxidants, fruits and vegetables and less meat, dairy and processed products has also been correlated with better semen quality.
Both the sperm and the eggs require a very high level of energy production. For the sperm, energy is needed for motility. For the egg, energy is needed for the proper segregation of the chromosomes and to expel one of each pair so that they can match up with the 23 chromosomes of the sperm to yield the 46 chromosomes of the adult cell. Disruptions of that process result in a higher miscarriage rate and contribute to the lower success rate of older couples. A high level of energy is also required for cell division into an embryo and by the rapidly dividing embryo. The egg has very high levels of energy-producing mitochondria, and oocyte mitochondrial DNA increases enormously during follicular growth. Co-enzyme Q-10 is critical to the transport of electrons and protons involved in the chemical reactions that drive ATP and therefore energy production by the mitochondria.
Smoking has major adverse effects on both sperm and egg quality. With female smoking, natural fertility is decreased and the chance of successful pregnancy with IVF is decreased by 50%. Although one would assume that the effects would be lesser in degree, second-hand smoke was found to have a similar effect on the outcome of VF compared with smoking. The effect is not only on egg quality. Recipients of egg donation who smoke also have a significantly lower pregnancy rate.
Alcohol also reduces fertility in both partners and alcohol intake by the male may increase miscarriage. In one study small amounts of caffeine and alcohol appeared to have additive or even synergistic effects in the female. As with most adverse life choices, the effects appear to be greater with the more advanced procedure of IVF. With the exception of couples just beginning to attempt conception, avoiding alcohol will give them the greatest chance of being successful.
Caffeine intake does not appear to affect male fertility unless it is excessive (over 3 cups of caffeinated coffee per day). However, female fertility is influenced to a greater degree, with moderate amounts reducing fertility and any significant intake reducing the success with IVF. Caffeine should not be used by pregnant women as it has been associated with miscarriage.
Stress and relaxation :
Finally, any discussion of life choices and fertility would be incomplete without discussing the effects of anxiety, stress, and depression. Various studies have shown a reduced success rate in achieving pregnancy in women experiencing these symptoms, and an intensive stress reduction program (Mind/Body) has been shown in controlled studies to reduce the time to achieve a pregnancy in couples just beginning to attempt conception and to increase the pregnancy rate with IVF.
How to improve egg qulity
Avoid taking alcohol, caffeine and smoking.
Live a healthy life style.
Eat good food.
Good hormonal fuels.
Protection from free radicals.
Good blood flow.